Objectives The last two years, clinical cases of tinea capitis caused by Trichophyton violaceum (T. violaceum), have been identified in Belgium. To better understand the emergence of this species in the ... [more ▼]

Objectives The last two years, clinical cases of tinea capitis caused by Trichophyton violaceum (T. violaceum), have been identified in Belgium. To better understand the emergence of this species in the population, the Belgian National Reference Center (NRC Liège) launched a one-year national survey in 2013. Epidemiological aspects and genotypic characterization of the strains were included. Methods The study was conducted from March 2013 up to February 2014. All Belgian laboratories were asked to send M. audouinii and T. violaceum strains isolated from hair to the NRC with a form to fill in including epidemiological data. The fungal strains were identified by microscopy or ITS sequencing in case of doubtful identification. The genotypic analysis was performed by the DiversiLab® system (bioMérieux) for DNA fingerprinting and analysis. Epidemiological data were analyzed with the help of a biostatistician. Results Amongst the collected isolates, 23 strains were confirmed as T.violaceum (results concerning the 116 M. audouinii strains have already been reported). Analysis of the epidemiological characteristics of the infected population shows that the main age category concerns 0-4 year-old children (n=9, 39,1%) with a sex-ratio M/F of 1.875. Data concerning the geographic origin of the family were present in 82,6% of the cases and reveal that patients were mainly of Ethiopian origin (n=8, 57,9% of known cases). One patient was also from Burundi showing that T. violaceum strains probably circulate mainly in East Africa. The genotypic analysis led to the distinction of 2 variants of T. violaceum. The major group was composed of 17 strains which were mainly collected in the North of Belgium and included also the reference strain (18/23, 83,3%). The other group (6 strains) was close to the major group but the analysis of the spectral superposition showed some differences between these two groups, defining two distinct variants of T. violaceum in the Belgian population. This second variant was mainly recovered from South Belgium (5/6, 83,3%). No correlation could be made between the genotypic group and a particular ethnical origin as Ethiopian subjects were found in both groups. Conclusion The DiversiLab® system proved to be an efficient method to investigate the molecular epidemiology of dermatophytes infections as reported previously for M. audouinii. These results show that two distinct isolates co-exist in Belgium providing evidence of genetic heterogeneity and a possible spread of one genotypic variant in a restricted geographic area or the co-existence of two variants circulating in different African communities. However, no clear correlation could be established between the appartenance to a group and epidemiological factors, such as age or ethnical origin. [less ▲]

Sensitivity, specificity and predictive values of an enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against bovine leukaemia virus (BLV) were evaluated using a representative sample of ... [more ▼]

Sensitivity, specificity and predictive values of an enzyme-linked immunosorbent assay (ELISA) for detecting antibodies against bovine leukaemia virus (BLV) were evaluated using a representative sample of 145 serum pools, comprising from 3 to 48 individual sera. The sample was constituted according to the frequency distribution of the negative and positive pools analysed during a screening involving the whole cattle population of Belgium. Sensitivity and specificity were estimated to 88.9% and 100% and the predicted negative and positive values were 99.9% and 100%, respectively. These results indicate the use of serum pools is suitable for the detection of BLV infected herds in eradication campaigns. [less ▲]

An enzyme-linked immunosorbent assay (ELISA), using monoclonal antibodies for capture and detection, was developed for detecting bovine viral diarrhoea virus (BVDV) antigens in blood samples. The test was ... [more ▼]

An enzyme-linked immunosorbent assay (ELISA), using monoclonal antibodies for capture and detection, was developed for detecting bovine viral diarrhoea virus (BVDV) antigens in blood samples. The test was evaluated using 761 field samples of known status (viraemic or not). When an appropriate cut-off value was chosen, the sensitivity, specificity, and predictive values of the assay were 100%, higher than the values obtained by classical virus isolation. Correlation with the latter technique exceeded 90%. The ELISA is a good candidate for replacing virus isolation as a reference method for BVDV antigen detection in persistently infected carriers. A method based on the mean of the standard deviation ratio can be used to choose the cut-off value in order to optimise reproducibility. [less ▲]

AIM: To document the epidemiologic patterns and risk factors of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections in Mali in order to develop prevention means for both diseases ... [more ▼]

AIM: To document the epidemiologic patterns and risk factors of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) infections in Mali in order to develop prevention means for both diseases. METHODS: Two prospective studies were conducted in Bamako in 2009 among 1000 pregnant women (i.e. , young women) who consulted six reference health centers, and in 2010, among 231 older women who attended general practice in two hospitals. Antibody tests and molecular analysis (performed only for HCV) were used to quantify the frequencies of both infections. The data were collected from patients recruited through a questionnaire. Transmission risk factors of both diseases were identified by univariate and multivariate analysis. RESULTS: HCV seroprevalence was 0.2% for young and 6.5% for older women. HIV prevalence was similar in both populations (4.1% vs 6.1%). In older women, the analysis of risk factors highlighted an association between HCV infection and episodes of hospitalization (P < 0.01). The study did not show an association between HIV infection and the variables such as hospitalization, transfusion, tattoo, dental care, and endoscopy. A significant decrease of HIV seroprevalence was detected in young women who used condoms for contraception more than for other purposes (P < 0.01). By contrast, HIV seroprevalence was significantly increased in young women using condoms mainly to prevent sexual infections rather than for contraception (P < 0.01). No HCV/HIV coinfection was detected in our study. CONCLUSION: Risk factors and epidemiologic data of HIV and HCV as well as the absence of co-infection strongly suggest epidemiological disparities between these diseases. [less ▲]

Rugby is a sport that is growing in popularity. A contact sport par excellence, it causes a significant number of injuries. In Rugby Union, there are 30 to 91 injuries per 1000 match hours. This ... [more ▼]

Rugby is a sport that is growing in popularity. A contact sport par excellence, it causes a significant number of injuries. In Rugby Union, there are 30 to 91 injuries per 1000 match hours. This epidemiological review of injuries incurred by rugby players mentions the position and type of injuries, the causes, time during the match and season in which they occur and the players’ positions as well as the length of players’ absences following the injury. [less ▲]

Zoonotic visceral leishmaniasis (VL), caused by Leishmania infantum is a vector-borne disease, transmitted to humans by the bite of infected female phlebotomine sand flies. In absence of treatment the ... [more ▼]

Zoonotic visceral leishmaniasis (VL), caused by Leishmania infantum is a vector-borne disease, transmitted to humans by the bite of infected female phlebotomine sand flies. In absence of treatment the outcome is death. The disease is characterised by irregular fever bouts, loss of weight, hepatosplenomegaly and anaemia. It is endemic in the Indian sub-continent and in East Africa. In the Mediterranean region, it is present in rural areas, in villages, in mountain areas, but also in certain peri-urban zones, where the parasites survive in dogs and other mammals. In fact, domestic dogs are the principal reservoir of human VL and they also can develop a more generalised and fatal form of the disease, although more than half of the dogs remain asymptomatic, the individual outcome depending on both cellular and humoral immune responses. Both symptomatic and asymptomatic dogs can infect the phlebotomine vectors, thereby enabling the transmission to other dogs or to people. This is the main reason why early detection and treatment of infected animals is the best way to reduce the risk of infection and, as such, forms an essential component in the prevention and control of the human disease. Ideally, a so-called “gold standard” test is required to reliably and correctly determine the infectious status of an individual and/or the infection prevalence in a population in a certain region at a certain point in time. A gold-standard test provides an error-free classification of individuals as infected or infection-free. The discriminative power of a real-life test is quantified by measures of precision, more specifically the sensitivity and the specificity of the test. They vary in function of characteristics of the population studied. In the majority of cases, a gold standard test does not exist. In order to overcome this lack, use is made of reference tests. The latter are often imperfect (sensitivity and specificity below one) and they allow estimation of a so-called apparent prevalence rather than the actual true prevalence. A statistical solution to the problem of lack of gold standard test consists of a Bayesian approach, which allows us to combine data of a study with external (prior, independent) information, such as results from previous studies or expert opinion. This approach yields an estimate of the true prevalence, as well as estimates of the sensitivity and specificity of the tests used. This thesis attempts to contribute towards a better understanding of the epidemiology of visceral leishmaniasis in Algeria. More specifically, our general objective (Chapter 3) was to estimate the true prevalence of canine leishmaniasis, in a situation where a diagnostic gold standard test was unavailable, and to describe the epidemiological curve and profile of visceral leishmaniasis in the country. With this in mind, the work is organised in nine chapters. The first chapter outlines the importance of leishmaniasis (respectively visceral and canine) in terms of public health and veterinary public health and provides an overview of the current knowledge base on canine leishmaniasis. The second chapter is devoted to a description of the epidemiological methodology available for the estimation of the true prevalence and the test characteristics in the absence of gold standard test. Chapter 4 describes an epidemiological study conducted in the capital city Algiers, comprising 462 dogs subdivided in four groups according to their function (stray dogs, guard dogs, farm dogs and pet dogs). A Bayesian approach was used to estimate the true prevalence of canine leishmaniasis in the four groups and to evaluate three serological tests: an indirect immunofluorescence test (IFAT), a direct agglutination test (DAT) and a commercial rapid test on gel, based on the protein rK39 (PaGIA). We were able to demonstrate variability in the test performance characteristics in the different groups, and this in terms of sensitivity and specificity. IFAT, although it is an imperfect test, is nevertheless the test of choice when the dog population targeted consists of stray dogs, but its specificity drops to a unsatisfactory 65.2% (IC: 60.2-73.5%) when applied to farm dogs: the fact of living together with other animals may induce cross-reactions. Stray dogs also yielded the highest estimate for the true prevalence (11.7%), probably a consequence of their constant living outside, which increases the risk of exposure to infected phlebotomine vectors. Using the above results, a large-scale transversal survey was mounted in six towns of the littoral zone of Algeria (Chapter 5). Thus, a total of 2,184 farm dogs and guard dogs were sampled in two distinct periods using two serological tests: before and after the main vector season, using IFAT and DAT. Serial and parallel interpretation of the combined tests were compared to various other statistical methods in order to estimate the true prevalence and the sensitivity and specificity of the two tests. The latent class model of Hui and Walter based on conditional independence between the diagnostic tests was compared to a Bayesian model, which made it possible to include conditional dependency between tests, if required. The best-adjusted model estimated canine leishmaniasis prevalence between 11% and 38% with an increasing trend from west to east. IFAT sensitivity varied between 86% and 88% in the different localities, whereas specificity ranged between 65% and 87%. DAT was invariably less sensitive than IFAT, but had a better specificity: between 80% and 95% in function of locality and season. The results highlighted once more the danger of considering IFAT to be a gold standard test for canine leishmaniasis. Chapter 6 draws up an epidemiological profile of human zoonotic visceral leishmaniasis in Algeria, based on cases notified to the National Public Health Institute between 1998 and 2008. A total of 1,562 were found for this period. This translates into an incidence rate of 0.45 cases per 100,000 inhabitants, of which 81.4% were children between zero and four years of age. Splenomegaly, fever, pallor and pancytopenia were the principal clinical and biochemical signs. Antimonies are the first-line treatment drugs in paediatric wards and amphotericin B injections are the treatment of choice in adults. Severe under-declaration (less than one case in ten notified) was demonstrated thanks to a survey carried out in the paediatric, internal medicine and infectious diseases departments of the five university hospital centres in Algiers, which had an influx of patients from all four corners of the country. Results of both Chapter 5 and Chapter 6 revealed a concordance between human visceral leishmaniasis incidence rates and true prevalence of canine leishmaniasis, providing extra support for the hypothesis that dogs are the main reservoir of the disease. Motivated by the results of the two surveys (Chapters 4 and 5), Chapter 7 describes a literature review of the performance of IFAT when used to estimate the canine leishmaniasis prevalence in the Mediterranean basin. Chapters 8 and 9 present the general discussion and conclusions and recommendations of the overall contribution of this research effort. Even though this work only represent a small addition to knowledge body on visceral leishmaniasis, it allowed us to better describe and understand the epidemiology of visceral leishmaniasis in Algeria and to obtain true prevalence estimates of canine leishmaniasis in various towns in the littoral zone of the country. It showed us the importance of correctly identifying and defining the target population of surveys to obtain the best possible posterior estimates and to optimise control measures. This work also showed the efficacy of the application of appropriate statistical models in a Bayesian framework when confronted with the absence of a gold standard test. Chapter 10 summarizes all references cited in the thesis. [less ▲]

Over a 16-month period, Klebsiella pneumoniae isolates from 102 patients admitted to a university hospital in Liege (Belgium) produced extended-spectrum beta-lactamases. Pulsed-field gel electrophoresis of genome macrorestriction patterns with XbaI and antibiotic susceptibility patterns subdivided 39 isolates into eight clonally related groups. Two of them were implicated in the course of this outbreak. They were responsible for successive waves of infection or colonization in different wards of the hospital while the others were encountered sporadically. A beta-lactamase with an isoelectric point of 7.6 and consistent with type SHV-2 characterized all nine isolates chosen among both major groups. [less ▲]

The prevalence of high blood pressure increases in our industrialized society. The main risk factors are hypertensive heredity, small birth weight for the gestational age, large increase of weight in ... [more ▼]

The prevalence of high blood pressure increases in our industrialized society. The main risk factors are hypertensive heredity, small birth weight for the gestational age, large increase of weight in teenagers, low physical activity, excess in salt and/or alcohol consumption. The normotensive people with high normal blood pressure are the future hypertensive population. [less ▲]

Trypanosoma evansi is an extracellular parasite, found in blood and tissues, mainly causing anaemia, immune depression and central nervous system disorders. Contrary to other African trypanosomes, T ... [more ▼]

Trypanosoma evansi is an extracellular parasite, found in blood and tissues, mainly causing anaemia, immune depression and central nervous system disorders. Contrary to other African trypanosomes, T. evansi is adapted to mechanical transmission and thus, presents a worldwide distribution. This review summarizes the epidemiological data about T. evansi from its origins to the latest developments, as its addition in 2008 to the World Organization for Animal Health (OIE) listed diseases and other diseases of importance to International Trade. This article puts emphasis on the need for a coordinated epidemiological control strategy and research for improving diagnostic and control tools. [less ▲]